Good maps are still being made. These put mine to shame, and remind me in many cases of Red Spectrum crossed with M2 and M1. Favorite: The Cylindrical. Great look, very vertical, and fun. Something I would have liked very much to play when I was more active.
The final edition of my third multiplayer mappack includes 20 maps for Marathon Infinity. This pack uses texture sets from all 3 games, with 5 Marathon 1 "themed" maps, 7 Durandal maps, and 8 standard Infinity maps.